HP FAX-750 Service Manual - Page 163

Troubleshooting

Page 163 highlights

2. TROUBLESHOOTING 2.1 Introduction This section gives the service personnel some of the troubleshooting procedures to be followed if an error or malfunction occurs with the facsimile equipment. It is impossible to anticipate all of the possible problems which may occur in future and determine the troubleshooting procedures, so this section covers some sample problems. However, those samples will help service personnel pinpoint and repair other defective elements if he/she analyzes and examines them well. 2.2 Precautions Be sure to observe the following to prevent the secondary troubles from happening: (1) Always unplug the AC power cord from the outlet when removing the covers and PCBs, adjusting the mechanisms, or conducting continuity testing with a circuit tester. (2) When disconnecting the connectors, do not pull the lead wires but hold the connector housings. (3) s Before handling the PCBs, touch a metal portion of the machine to discharge static electricity charged in your body. s When repairing the PCBs, handle them with extra care. After repairing the defective section, be sure to check again if the repaired section works correctly. Also record the troubleshooting procedure so that it would be of use for future trouble occurrence. 2.3 Checking prior to Troubleshooting Prior to proceeding to the troubleshooting procedures given in Subsection 2.4, check that : (1) Each voltage level on AC input lines and DC lines is correct. (2) All cables and harnesses are firmly connected. (3) None of the fuses are blown. VI - 12

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VI
- 12
2. TROUBLESHOOTING
2.1
Introduction
This section gives the service personnel some of the troubleshooting procedures to be followed if
an error or malfunction occurs with the facsimile equipment.
It is impossible to anticipate all of the
possible problems which may occur in future and determine the troubleshooting procedures, so this
section covers some sample problems.
However, those samples will help service personnel
pinpoint and repair other defective elements if he/she analyzes and examines them well.
2.2
Precautions
Be sure to observe the following to prevent the secondary troubles from happening:
(1)
Always unplug the AC power cord from the outlet when removing the covers and PCBs,
adjusting the mechanisms, or conducting continuity testing with a circuit tester.
(2)
When disconnecting the connectors, do not pull the lead wires but hold the connector
housings.
(3)
Before handling the PCBs, touch a metal portion of the machine to discharge static
electricity charged in your body.
When repairing the PCBs, handle them with extra care.
After repairing the defective section, be sure to check again if the repaired section works correctly.
Also record the troubleshooting procedure so that it would be of use for future trouble occurrence.
2.3
Checking prior to Troubleshooting
Prior to proceeding to the troubleshooting procedures given in Subsection 2.4, check that :
(1)
Each voltage level on AC input lines and DC lines is correct.
(2)
All cables and harnesses are firmly connected.
(3)
None of the fuses are blown.